The incidence of neonatal HSV infection is one in 2,500-5000 live births, with a higher incidence in certain areas of the United States. Approximately 45-50% of those infected have disease limited to the skin, eye, and mouth. Unfortunately, 10% of these babies still have significant neurological deficits. Part I: The purpose of this study is to determine if high dose acyclovir (60 mg/kg/day) is safe and well tolerated in the newborn and whether it appears to decrease morbidity and mortality of central nervous system (CNS) or disseminated neonatal herpes simplex virus (HSV) infection both acutely and on long term follow-up. Part II: The purpose of this study is to determine if suppressive therapy with oral acyclovir will decrease the recurrence of skin lesions in neonatal herpes simplex virus (HSV) infections involving skin, eye and mouth, and eliminate the longterm neurologic impairment. In earlier studies it was noted that the number of skin recurrences correlated directly with the degree of neurological impairment, even with initial parenteral therapy. This would imply a possibility of reactivation of the virus at other sites over time. Suppressive therapy may have the potential to prevent this reactivation and thus eliminate neurological impairment in this group.